Camphoric acid salts as inhibitors for water soluble fuels



Etates Patent 2,715,572 Patented Aug. 16, 1955 CAMPHORIC ACID SALTS AS ITORS FOR WATER SOLUBLE FUELS Karl F. Hager, Huntsville, Ala, and Morris Rosenthal, Alexandria, Va., assignors, by direct md mesue assignments, to the United States of America as represented by the Secretary of the Army No Drawing. Application September 13, 1951, Serial No. 246,522

7 Claims. (Cl. 4455) This invention relates to the prevention of corrosion.

In many new developments water-soluble organic compounds are used as fuel. In the case of iron or steel containers or equipment, these water-soluble organic fuels exhibit a definite corrosive effect. Corrosion attacks the metal causing the economic loss of the ferrous materials as well as weakening the strength of the equipment. Products of corrosion roughen the metallic surfaces and consequently in pipes increase the power requirements for the desired rate of flow. The products of corrosion may also clog up small orifices in the path of the fluid fiow and cause disruption of the fuel system.

Accordingly the primary object of our invention is to develop a new and efiicient means for preventing corrosion. A further object is to develop means for preventing the corrosion of metallic surfaces which contact organic fuels.

Corrosion may be prevented by several methods. Materials may be chosen for their corrosion resistant properties. Surfaces may be coated or otherwise passivated against corrosive attack. We have chosen however to prevent the corrosion by adding an agent to the corrosive liquid to render the liquid itself passive or inhibit its corrosive properties. A third object of the invention is therefore the development of an agent which when added to corrosive liquids, fuels in particular will render them harmless to metals. Other objects of our invention will appear hereinafter.

Alkaline organic and inorganic inhibitors are known as corrosion preventing agents. The disadvantages of inorganic inhibitors are that they do not aid the heating value per unit quantity of the fuel and that they leav solid residues after combustion of the organic materials. Alkaline organic inhibitors are useful where light metals, such as aluminum, do not come in contact with the inhibited fuels. Aluminum and magnesium are attacked by alkalies.

The inhibitor we have discovered consists of neutral salts of camphoric acid. These materials act as inhibitors protecting ferrous metals from corrosion and do not attack light metals. Thus they are applicable to an airplane fuel at all points in its distribution. They can be put into the fuels at ground installations, stored in ferrous metal containers and then loaded into light metal containers in aircraft where weight is an important factor. All the containers are protected against the corrosive effects of the water soluble organic fuel.

The following examples are given to illustrate our invention and to point out its advantages:

Example ].-A mild steel container was half filled with a 75% ethanol-25% water solution. Within one day corrosion of the container was noted. With the passage of time corrosion increased steadily.

Example 2.A mild steel container was half filled with a 75% ethanol- 25% water solution to which 0.1% of neutralized sodium camphorate was added. After one year only one small spot of corrosion was noted.

I with a 50:50

The surface remained shiny, 99.9% inhibited.

Example 3.A mild steel container was half filled with a 50:50 acetone-water solution. Corrosion products were observed in one day. As the time of exposure of the metal to the water-soluble organic fuel increased, the severity of the corrosion increased.

Example 4.A mild steel container was half filled acetone-water solution to which 0.1% of neutralized ammonium camphorate was added. After one year the steel container was not corroded. Corrosion inhibition was well over 99.99%.

Example 5.Examples 2 and 4 were duplicated subtituting the potassium and other neutral camphoric acid salts in 0.1% concentration with the result that the containers were not corroded.

We do not intend our invention to be limited by the illustrative examples above but solely by the scope of the appended claims.

What we claim is:

l. The method of inhibiting the corrosive properties of low molecular weight water-soluble organic liquids selected from the group consisting of ethanol and acetone, which comprises supplying a neutral camphoric acid salt thereto in an amount constituting about 0.1% by weight of the total, said salt being selected from the group consisting of alkali metal salts and ammonium salts of camphoric acid.

2. A corrosion inhibited fuel comprising water in an amount up to about 50% by weight of the total, a combustible water-soluble organic liquid of low molecular weight selected from the group consisting of ethanol and acetone, the water being present in an amount constituting a substantial proportion of the total, and a neutral salt forming about 0.1% by weight of the total, said salt being selected from the group consisting of alkali metal salts of camphoric acid and ammonium salts of camphoric acid.

and corrosion was over 3. A non-corrosive fuel comprising water, a watersoluble combustible liquid of low molecular weight selected from the group consisting of ethanol and acetone, the combustible liquid being present in an amount constituting at least 50% by weight of the total, and a neutral salt forming about 0.1% by Weight of the total, said salt being selected from the group consisting of the alkali metal salts of camphoric acid and ammonium salts of camphoric acid.

4. A corrosion inhibited fuel comprising 99.9% of a -25 ethanol-water solution, and 0.1% neutral sodium camphorate.

5. A corrosion inhibited fuel comprising 99.9% of a 50-50 acetone-water solution, and 0.1% neutral ammonium camphorate.

6. A corrosion inhibited fuel comprising 99.9% of a 75-25 ethanol-water solution, and 0.1% neutral potassium camphorate.

7. A corrosion inhibited fuel comprising 99.9% of a 5050 acetone-water solution, and 0.1% neutral potassium camphorate.

References Cited in the file of this patent UNITED STATES PATENTS 1,915,148 Berliner June 20, 1933 1,927,842 McDermott Sept. 26, 1933 1,930,284 Morrell Oct. 10, 1933 2,491,741 Ledrut Dec. 20, 1949 OTHER REFERENCES Rahway, 

2. A CORROSION INHIBITED FUEL COMPRISING WATER IN AN AMOUNT UP TO ABOUT 50% BY WEIGHT OF THE TOTAL, A COMBUSTIDE WATER-SOLUBLE ORGANIC LIQUID OF LOW MOLECULAR WEIGHT SELECTED FROM THE GROUP CONSISTING OF ETHANOL AND ACETONE, THE WATER BEING PRESENT IN AN AMOUNT CONSTITUTING A SUBSTANTIAL PROPORTION OF THE TOTAL, AND A NEUTAL SALT FORMING ABOUT 0.1% BY WEIGHT OF THE TOTAL, SAID SALT BEING SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL SALTS OF CAMPHORIC ACID AND AMMONIUM SALTS OF CAMPHORIC ACID. 